<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>frozenSet</title>
</head>

<body>
    <div>打开浏览器控制台查看结果</div>
    <script>
        const frozenSet = iterable => {
            const s = new Set(iterable);
            s.delete = undefined;
            s.add = undefined;
            s.clear = undefined;
            return s;
        };
        console.log(frozenSet([1, 2, 3, 1, 2]));
    </script>
</body>

</html>